Field
Exemplary embodiments of the present invention relate a liquid crystal display and a driving method, and more particularly, to a liquid crystal display and a driving method with an improved afterimage.
Discussion of the Background
A liquid crystal display (LCD), which is one of the most common types of display devices currently in use, includes two display panels with electrodes and a liquid crystal layer interposed therebetween. The liquid crystal display generates an electric field by applying a voltage to the electrodes to realign liquid crystal molecules of the liquid crystal layer and thus, control transmittance of light so as to display images.
The liquid crystal display includes thin film transistors, a gate line and a data line which cross each other are formed on the display panel of the liquid crystal display including the thin film transistors, and a pixel corresponding to an area in which a screen is displayed is connected to the thin film transistor.
When the thin film transistor is turned on by applying a gate-on voltage to the gate line, a data voltage applied through the data line is charged in the pixel. The alignment state of the liquid crystal layer is determined depending on the electric field formed between a pixel voltage charged in the pixel and a common voltage applied to a common electrode. The data voltage may be applied by varying a polarity for each frame.
The data voltage applied to the pixel is shifted by a parasitic capacitance Cgs between a gate electrode and a source electrode to form the pixel voltage. In this case, the shifted voltage is referred to as a kickback voltage.
The value of the kickback voltage is changed according to a gray level and a polarity of the data voltage so that the pixel voltage varies for every frame. As a result, a flicker defect due to a luminance difference occurs, and there is a problem in that the liquid crystal layer is influenced by a residual DC voltage to form an afterimage. In order to solve a DC afterimage due to the residual DC voltage and the like, an asymmetrical gamma correction method in which the data voltage is compensated for each gray level and the like have been attempted, but separately, an AC afterimage then becomes a problem.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.